(1) Field of the Invention
The present invention relates to a map information display apparatus and method for displaying a map for a mobile object, and especially relates to a map information display apparatus and method for displaying, together with a map, an estimated transit time of a point on the map.
(2) Description of the Related Art
Nowadays, a map display apparatus such as a car navigation apparatus or a mobile terminal navigation apparatus of a mobile phone and the like displays an arrival time at a final destination which is set by a user. Displaying the arrival time allows the user to know whether or not the user can be in time at the final destination, and travel without worry. Moreover, the arrival time can be utilized by the user to decide whether or not to stop off somewhere on the way to the final destination.
In cases such as where there is a long distance to the final destination, the final destination has not been determined yet, or the user wants to stop at a place, such as a service area, other than the final destination, it is equally effective to display a transit time of a position other than the final destination. Even though the position for which the transit time is displayed is different from the final destination, the transit time display is effective because the user can estimate a transit time of a neighborhood of the transit time display position based on the displayed transit time.
For example, a vehicle navigation apparatus described in Japanese Unexamined Patent Application Publication No. 2004-286456 (hereinafter referred to as Patent Reference 1) displays, when a final destination is set by a user, transit times of main intersections on a travel route to the final destination on a map. Further, the navigation apparatus changes positions for which transit times are displayed, according to a scale of the displayed map.
When displaying images or characters on a map, it is important to make the display easy to view. For example, a vehicle navigation apparatus described in Japanese Patent Application Publication No. 10-153449 (hereinafter referred to as Patent Reference 2) limits, when displaying landmarks on a map, the number of landmarks displayed on the map to a predetermined number, to make the display easily viewable.
However, for instance, the navigation apparatus described in Patent Reference 1 has a problem of not displaying the transit times unless the user sets the final destination.
Furthermore, even in the case where the user wants to stop off somewhere away from the travel route to the final destination, the navigation apparatus described in Patent Reference 1 displays only the transit times on the travel route to the final destination. On the other hand, if transit times of all main intersections on the map are displayed, the number of displayed transit times increases and display positions become dense, which hinders the user's understanding. Even when the number of positions for which transit times are displayed is limited to a predetermined number as in the vehicle navigation apparatus described in Patent Reference 2, another problem arises when displaying transit times. That is, merely limiting the number can result in concentration of transit time display positions as shown in FIG. 62.
Usually, the user can estimate a transit time of a neighborhood of a transit time display position, based on a road distance. However, when transit time display positions concentrate northwest of a current position as shown in FIG. 62, the user cannot know a transit time of a position other than northwest. Such a display is useless. Therefore, it is necessary to display transit times in a more scattered manner, as shown in FIG. 63.
In view of this, the present invention has an object of providing a map information display apparatus and method that can provide an easily viewable display to a user.